Merge branch 'for-linus' of git://git.kernel.dk/linux-block

[pandora-kernel.git] / net / ipv4 / tcp_cubic.c

diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 34340c9..f376b05 100644 (file)
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -93,6 +93,7 @@ struct bictcp {
        u32     ack_cnt;        /* number of acks */
        u32     tcp_cwnd;       /* estimated tcp cwnd */
 #define ACK_RATIO_SHIFT        4
+#define ACK_RATIO_LIMIT (32u << ACK_RATIO_SHIFT)
        u16     delayed_ack;    /* estimate the ratio of Packets/ACKs << 4 */
        u8      sample_cnt;     /* number of samples to decide curr_rtt */
        u8      found;          /* the exit point is found? */
@@ -398,8 +399,12 @@ static void bictcp_acked(struct sock *sk, u32 cnt, s32 rtt_us)
        u32 delay;
 
        if (icsk->icsk_ca_state == TCP_CA_Open) {
-               cnt -= ca->delayed_ack >> ACK_RATIO_SHIFT;
-               ca->delayed_ack += cnt;
+               u32 ratio = ca->delayed_ack;
+
+               ratio -= ca->delayed_ack >> ACK_RATIO_SHIFT;
+               ratio += cnt;
+
+               ca->delayed_ack = min(ratio, ACK_RATIO_LIMIT);
        }
 
        /* Some calls are for duplicates without timetamps */